Module#prepend

* class.c (rb_prepend_module): prepend module into another module.
* eval.c (rb_mod_prepend): new method Module#prepend.  [Feature #1102]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@36234 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

9 files changed, 148 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 8145a70a17..310f6250a3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Wed Jun 27 16:48:48 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* class.c (rb_prepend_module): prepend module into another module.
+
+	* eval.c (rb_mod_prepend): new method Module#prepend.  [Feature #1102]
+
 Wed Jun 27 09:15:46 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* io.c (is_popen_fork): check if fork and raise NotImplementedError if
diff --git a/class.c b/class.c
index daaf401497..fc3b483735 100644
--- a/class.c
+++ b/class.c
@@ -56,6 +56,7 @@ class_alloc(VALUE flags, VALUE klass)
     RCLASS_CONST_TBL(obj) = 0;
     RCLASS_M_TBL(obj) = 0;
     RCLASS_SUPER(obj) = 0;
+    RCLASS_ORIGIN(obj) = (VALUE)obj;
     RCLASS_IV_INDEX_TBL(obj) = 0;
     return (VALUE)obj;
 }
@@ -687,6 +688,8 @@ rb_include_module(VALUE klass, VALUE module)
 		break;
 	    }
 	}
+	if (c == klass)
+	    c = RCLASS_ORIGIN(klass);
 	c = RCLASS_SUPER(c) = include_class_new(module, RCLASS_SUPER(c));
 	if (RMODULE_M_TBL(module) && RMODULE_M_TBL(module)->num_entries)
 	    changed = 1;
@@ -696,6 +699,45 @@ rb_include_module(VALUE klass, VALUE module)
     if (changed) rb_clear_cache();
 }
 
+void
+rb_prepend_module(VALUE klass, VALUE module)
+{
+    VALUE p, c, origin;
+
+    rb_frozen_class_p(klass);
+    if (!OBJ_UNTRUSTED(klass)) {
+	rb_secure(4);
+    }
+
+    Check_Type(module, T_MODULE);
+
+    OBJ_INFECT(klass, module);
+    c = RCLASS_SUPER(klass);
+    if (RCLASS_M_TBL(klass) == RCLASS_M_TBL(module))
+	rb_raise(rb_eArgError, "cyclic include detected");
+    for (p = c; p; p = RCLASS_SUPER(p)) {
+	if (BUILTIN_TYPE(p) == T_ICLASS) {
+	    if (RCLASS_M_TBL(p) == RCLASS_M_TBL(module)) {
+		rb_raise(rb_eArgError, "already prepended module");
+	    }
+	}
+    }
+    origin = RCLASS_ORIGIN(klass);
+    if (origin == klass) {
+	origin = class_alloc(T_ICLASS, rb_cClass);
+	RCLASS_SUPER(origin) = RCLASS_SUPER(klass);
+	RCLASS_SUPER(klass) = origin;
+	RCLASS_ORIGIN(klass) = origin;
+	RCLASS_M_TBL(origin) = RCLASS_M_TBL(klass);
+	RCLASS_M_TBL(klass) = 0;
+	c = origin;
+    }
+    RCLASS_SUPER(klass) = include_class_new(module, c);
+    if (RMODULE_M_TBL(module) && RMODULE_M_TBL(module)->num_entries) {
+	rb_clear_cache_by_class(klass);
+    }
+}
+
 /*
  *  call-seq:
  *     mod.included_modules -> array
diff --git a/eval.c b/eval.c
index 1203a20ecc..37bb35a148 100644
--- a/eval.c
+++ b/eval.c
@@ -954,6 +954,58 @@ rb_mod_include(int argc, VALUE *argv, VALUE module)
     return module;
 }
 
+/*
+ *  call-seq:
+ *     prepend_features(mod)   -> mod
+ *
+ *  When this module is prepended in another, Ruby calls
+ *  <code>prepend_features</code> in this module, passing it the
+ *  receiving module in _mod_. Ruby's default implementation is
+ *  to overlay the constants, methods, and module variables of this module
+ *  to _mod_ if this module has not already been added to
+ *  _mod_ or one of its ancestors. See also <code>Module#prepend</code>.
+ */
+
+static VALUE
+rb_mod_prepend_features(VALUE module, VALUE prepend)
+{
+    switch (TYPE(prepend)) {
+      case T_CLASS:
+      case T_MODULE:
+	break;
+      default:
+	Check_Type(prepend, T_CLASS);
+	break;
+    }
+    rb_prepend_module(prepend, module);
+
+    return module;
+}
+
+/*
+ *  call-seq:
+ *     prepend(module, ...)    -> self
+ *
+ *  Invokes <code>Module.prepend_features</code> on each parameter in reverse order.
+ */
+
+static VALUE
+rb_mod_prepend(int argc, VALUE *argv, VALUE module)
+{
+    int i;
+    ID id_prepend_features, id_prepended;
+
+    CONST_ID(id_prepend_features, "prepend_features");
+    CONST_ID(id_prepended, "prepended");
+    for (i = 0; i < argc; i++)
+	Check_Type(argv[i], T_MODULE);
+    while (argc--) {
+	rb_funcall(argv[argc], id_prepend_features, 1, module);
+	rb_funcall(argv[argc], id_prepended, 1, module);
+    }
+    return module;
+}
+
 void
 rb_obj_call_init(VALUE obj, int argc, VALUE *argv)
 {
@@ -1213,6 +1265,8 @@ Init_eval(void)
     rb_define_private_method(rb_cModule, "append_features", rb_mod_append_features, 1);
     rb_define_private_method(rb_cModule, "extend_object", rb_mod_extend_object, 1);
     rb_define_private_method(rb_cModule, "include", rb_mod_include, -1);
+    rb_define_private_method(rb_cModule, "prepend_features", rb_mod_prepend_features, 1);
+    rb_define_private_method(rb_cModule, "prepend", rb_mod_prepend, -1);
 
     rb_undef_method(rb_cClass, "module_function");
 
diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index 626f283ed2..23ba7535f2 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -1080,6 +1080,7 @@ VALUE rb_define_module_under(VALUE, const char*);
 
 void rb_include_module(VALUE,VALUE);
 void rb_extend_object(VALUE,VALUE);
+void rb_prepend_module(VALUE,VALUE);
 
 struct rb_global_variable;
 
diff --git a/internal.h b/internal.h
index 51d71d7cab..77e6c2e191 100644
--- a/internal.h
+++ b/internal.h
@@ -27,6 +27,7 @@ struct rb_classext_struct {
     VALUE super;
     struct st_table *iv_tbl;
     struct st_table *const_tbl;
+    VALUE origin;
 };
 
 #undef RCLASS_SUPER
@@ -36,6 +37,7 @@ struct rb_classext_struct {
 #define RCLASS_CONST_TBL(c) (RCLASS_EXT(c)->const_tbl)
 #define RCLASS_M_TBL(c) (RCLASS(c)->m_tbl)
 #define RCLASS_IV_INDEX_TBL(c) (RCLASS(c)->iv_index_tbl)
+#define RCLASS_ORIGIN(c) (RCLASS_EXT(c)->origin)
 
 struct vtm; /* defined by timev.h */
 
diff --git a/object.c b/object.c
index ac8fa53104..6e42043a55 100644
--- a/object.c
+++ b/object.c
@@ -2862,6 +2862,7 @@ Init_Object(void)
     rb_define_private_method(rb_cClass, "inherited", rb_obj_dummy, 1);
     rb_define_private_method(rb_cModule, "included", rb_obj_dummy, 1);
     rb_define_private_method(rb_cModule, "extended", rb_obj_dummy, 1);
+    rb_define_private_method(rb_cModule, "prepended", rb_obj_dummy, 1);
     rb_define_private_method(rb_cModule, "method_added", rb_obj_dummy, 1);
     rb_define_private_method(rb_cModule, "method_removed", rb_obj_dummy, 1);
     rb_define_private_method(rb_cModule, "method_undefined", rb_obj_dummy, 1);
diff --git a/test/ruby/test_module.rb b/test/ruby/test_module.rb
index b24fa3222d..decb217289 100644
--- a/test/ruby/test_module.rb
+++ b/test/ruby/test_module.rb
@@ -1238,4 +1238,36 @@ class TestModule < Test::Unit::TestCase
     INPUT
     assert_in_out_err([], src, ["NameError"], [])
   end
+
+  module M0
+    def m1; [:M0] end
+  end
+  module M1
+    def m1; [:M1, super, :M1] end
+  end
+  module M2
+    def m1; [:M2, super, :M2] end
+  end
+  M3 = Module.new do
+    def m1; [:M3, super, :M3] end
+  end
+  module M4
+    def m1; [:M4, super, :M4] end
+  end
+  class C0
+    include M0
+    prepend M1
+    def m1; [:C0, super, :C0] end
+  end
+  class C1 < C0
+    prepend M2, M3
+    include M4
+    def m1; [:C1, super, :C1] end
+  end
+
+  def test_prepend
+    obj = C1.new
+    expected = [:M2,[:M3,[:C1,[:M4,[:M1,[:C0,[:M0],:C0],:M1],:M4],:C1],:M3],:M2]
+    assert_equal(expected, obj.m1)
+  end
 end
diff --git a/vm_insnhelper.c b/vm_insnhelper.c
index 2e00c0e1de..6544ed89fc 100644
--- a/vm_insnhelper.c
+++ b/vm_insnhelper.c
@@ -1425,6 +1425,7 @@ static inline VALUE
 vm_search_normal_superclass(VALUE klass, VALUE recv)
 {
     if (BUILTIN_TYPE(klass) == T_CLASS) {
+	klass = RCLASS_ORIGIN(klass);
 	return RCLASS_SUPER(klass);
     }
     else if (BUILTIN_TYPE(klass) == T_MODULE) {
diff --git a/vm_method.c b/vm_method.c
index c9f0130512..5a7722cd67 100644
--- a/vm_method.c
+++ b/vm_method.c
@@ -169,6 +169,9 @@ rb_method_entry_make(VALUE klass, ID mid, rb_method_type_t type,
 		     rb_method_definition_t *def, rb_method_flag_t noex)
 {
     rb_method_entry_t *me;
+#if NOEX_NOREDEF
+    VALUE rklass;
+#endif
     st_table *mtbl;
     st_data_t data;
 
@@ -194,6 +197,10 @@ rb_method_entry_make(VALUE klass, ID mid, rb_method_type_t type,
     }
 
     rb_check_frozen(klass);
+#if NOEX_NOREDEF
+    rklass = klass;
+#endif
+    klass = RCLASS_ORIGIN(klass);
     mtbl = RCLASS_M_TBL(klass);
 
     /* check re-definition */
@@ -205,7 +212,7 @@ rb_method_entry_make(VALUE klass, ID mid, rb_method_type_t type,
 #if NOEX_NOREDEF
 	if (old_me->flag & NOEX_NOREDEF) {
 	    rb_raise(rb_eTypeError, "cannot redefine %"PRIsVALUE"#%"PRIsVALUE,
-		     rb_class_name(klass), rb_id2str(mid));
+		     rb_class_name(rklass), rb_id2str(mid));
 	}
 #endif
 	rb_vm_check_redefinition_opt_method(old_me, klass);
@@ -384,7 +391,7 @@ search_method(VALUE klass, ID id)
 	return 0;
     }
 
-    while (!st_lookup(RCLASS_M_TBL(klass), id, &body)) {
+    while (!RCLASS_M_TBL(klass) || !st_lookup(RCLASS_M_TBL(klass), id, &body)) {
 	klass = RCLASS_SUPER(klass);
 	if (!klass) {
 	    return 0;